I've read a few stories of people who say they started a little more conservatively than necessary but I can't say I ever have. However, as I tell people who are looking for guidance, it is much better to be 30 seconds too slow at the first mile than 30 seconds too fast. My point is even a little too fast can burn you but too slow, within reason, can in large part be made up later in the race.

Actually, to be honest, I believe I only started too fast once. Every other start was about right. Twice, it was mistakes in places other than the first 2-3 miles that burned me.

I ran a large negative split of 3-4 minutes twice (of 11 marathons). It's NOT the optimal stategy for your best time but it does minimize discomfort. I ran a pb in those 2 races but my overall best time came with even splits.

It's best to 'err' on the side of the negative split but try to keep it under 2 minutes.

I have. In 12/05 I ran my best marathon to date, 2:52:56 which is a 6:36 pace. I purposely planned to go out the first mile around 7:00 so I decided to go out with the sub 3 pace group. They ran mile 1 in 7:35. Add in the fact that for some reason my legs felt way too lethargic and I ran 7:35, 6:55, and 7:10. I went through the half in 1:28:30 and ran the second half in 1:24:26. I wouldn't mind a small negative split on that course as the first half has some small hills and the 2nd half in 100% flat, but that was too much. I think I could have been close to sub 2:50 if I hadn't gotten off to such a rotten start.

One bonus is that the 2nd half was fun. I was passing people left and right in the final 10k.